Decibel Calculator vs Sound Level Converter
Both of these pages work with decibels, and both warn that dB values cannot simply be added like ordinary numbers. But they sit on different sides of sound measurement. The decibel calculator is logarithmic math: it turns dB into ratios, ratios into dB, and two sound levels into one combined level. The sound level converter is a translation tool: it moves one sound level between the decibel, phon, and sone scales under a stated 1 kHz assumption. Choosing between them is a question of whether you are doing dB arithmetic or converting loudness units.
What each calculator does
The decibel calculator offers three modes. dB to ratio converts a decibel value into a power or intensity ratio (multiplier 10) or an amplitude or pressure ratio (multiplier 20). Ratio to dB works the other way from a positive ratio. Combine mode adds two sound levels logarithmically — for example, 65 dB and 68 dB combine to about 69.76 dB, not 133 dB. Decibel inputs are accepted from -200 through 200, and ratio inputs must be finite and greater than zero.
The sound level converter takes one sound level and converts it among decibel, phon, and sone. Under the calculator’s 1 kHz assumption, dB equals phon, phon converts to sone with 2^((phon − 40)/10), and sone converts back with 40 + 10·log₂(sone). Its default example, 60 dB, becomes 60 phon and 4.0 sones. The input must be nonnegative, and a sone source must be greater than zero because the reverse formula needs a logarithm.
Side-by-side comparison
| Feature | Decibel calculator | Sound level converter |
|---|---|---|
| Task | dB ↔ ratio, and combine two levels | Convert one level between dB, phon, and sone |
| Units handled | dB and dimensionless ratios | dB, phon, sone |
| Combining sources | Yes — logarithmic level addition | No — one sound level at a time |
| Key formula | 10·log₁₀(P₂/P₁), 20·log₁₀(A₂/A₁), or 10·log₁₀(10^(L₁/10) + 10^(L₂/10)) | phon = dB; sone = 2^((phon − 40)/10) |
| Worked example | 65 dB + 68 dB → 69.76 dB | 60 dB → 60 phon → 4.0 sones |
| Input limits | dB −200 to 200; ratio greater than zero | Nonnegative value; sone greater than zero |
| Weighting | None — generic dB arithmetic | None — 1 kHz loudness model |
When to use which
Use the decibel calculator when the question is about the logarithmic relationship itself: how many dB correspond to a power ratio of 100 (20 dB), what ratio a negative dB reading represents, or what one equivalent level results from two independent sound sources. Its combine mode is the safe replacement for the common mistake of adding two dB readings directly — two equal sources increase the level by about 3.01 dB, not double it.
Use the sound level converter when you have one sound level and want it in different units for communication: what 60 dB means as phons and sones, how many sones correspond to a 70-phon loudness level, or how to state a fan’s sone rating as dB. Keep its 1 kHz simplification visible — the equality of dB and phon does not hold at other frequencies, where human hearing sensitivity changes.
Neither page is a measurement or safety tool. The decibel calculator assumes a reference has already been chosen and does not apply weighting, time averaging, or calibration; the sound level converter is a loudness model, not a calibrated sound meter or audiology test. For questions about exposure duration and workplace limits, use the noise exposure calculator instead.
Where to start
- Decibel calculator — dB to ratio, ratio to dB, and combining two sound levels.
- Sound level converter — translating one level between decibel, phon, and sone.